Heavy metals in molted fur of the southern elephant seal Mirounga leonina.

Heavy metal concentrations in marine mammals have been reported for different environments, including the Baltic Sea (Szefer et al., 2002), Mediterranean Sea (Cardellicchio et al., 2002), North and South Atlantic Oceans (Marcovecchio et al., 1994; Das et al., 2003) and the Polar Regions (de Moreno et al., 1997; Fisk et al., 2005). In the case of the Antarctic (Yamamoto et al., 1987; Szefer et al., 1994; de Moreno et al., 1997), the available studies have important limitations. Marine mammals are legally protected by the Protocol on Environmental Protection to the Antarctic Treaty (1991), which limits to a great degree the ability of researchers to make reliable determinations of element contents in different organs and tissues of marine mammals. In spite of the problems associated in working with internal tissues, limited attention has been paid to non-destructive protocols using hair, skin or fur samples, which provide a simpler and harmless way of assessing the level of heavy metals in marine mammals (Fossi and Marsili, 1997). The southern elephant seal Mirounga leonina is a large deep-diving, top-level predator that spends more than 80% of its life-cycle at sea (Hindell et al., 1991). This species forages throughout most of the Southern Ocean, travels large distances from land, and consumes large quantities of squid and fish (Daneri and Carlini, 2002; Bradshaw et al., 2003). As with other species of pinnipeds, M. leonina molts annually, providing a periodic source of material for analysis without having to disturb or manipulate the animals. Furthermore, mammal fur and hairs are commonly used as target tissues to assess levels of a wide diversity of substances, including metals (Schramm, 1997; Rashed and Soltan, 2005). However, this approach has been mainly used in terrestrial mammals, where hair is a good monitoring tool as it reflects the content of heavy metals in the forage and soil (Rashed and Soltan, 2005). In this context, and given the lack of information on heavy metals in the southern elephant seal, concentrations of Cd, Cu, Cr, Ni, Pb and Zn were determined in molted fur samples of M. leonina from the South Shetland Islands. The aim of the study was to provide a baseline of heavy metals at the top level of the Antarctic marine food web, and to assess the reliability of molted fur samples as a harmless sampling tool for heavy metals assessment in seals. Several hundred elephant seals haul out at an area around Stranger Point (62 14 0S; 58 40 0W), on King George Island. Juveniles haul out to molt in late November and December; adult females molt in January and February; and adult males haul out from March to April (Daneri and Carlini, 2002). Molted fur samples of 27 three-yearThe objective of BASELINE is to publish short communications on different aspects of pollution of the marine environment. Only those papers which clearly identify the quality of the data will be considered for publication. Contributors to Baseline should refer to ‘Baseline—The New Format and Content’ (Mar. Pollut. Bull. 42, 703–704).